2007 Annual Report 1a.Objectives (from AD-416) Develop and validate a new method designed to estimate methane emissions from landfills taking into account the oxidation of methane in cover soil and other parameters. 1b.Approach (from AD-416) Determine data needs, consult available data bases and validate data. Create a field and laboratory validated methane oxidation sub-model. Develop an integrated landfill methane mass balance model for California. This model will include the following sub-models: Methane Generation, Methane Recovery, Methane Emission, Methane Oxidation, Methane Migration, Change in Storage and Methane Balance. Field scale validation will be done at a minimum of two sites in California. Statistically analyze the field monitoring data to determine emission trends and dependent variables. 3.Progress Report This report serves to document accomplishments under a reimbursable agreement between ARS and Landfills+, Inc. Additional details of research can be found in the parent project 3645-11000-003-00D. The objective of this three-year cooperative research project is to develop and validate a new method designed to estimate methane emissions from landfills taking into account the oxidation of methane in cover soil by soil bacteria (methanotrophic bacteria). As much as possible, the model will be driven by data currently collected and compiled by regulatory agencies. To accomplish these tasks, research was initiated in February 2007. The project is currently on-schedule or slightly ahead of schedule. Current year accomplishments were: 1) Contact was established with the state regulator agencies and initial site data was collected. 2) Feedback is being gathered on the current data template with regulators including members of the California’s Integrated Waste Management Board, Public Interest Energy Research, and California’s Air Resource Board as well as the technical advisory committee for the project. 3) Initial field gas emission monitoring was completed, including methane fluxes and soil gas profiles. 4) Installed weather station and soil microclimate monitoring equipment at the two field validation sites. 5) Collected soil samples of the three cover types (daily, intermediate, and final cover) for laboratory incubation and testing. Laboratory batch incubations for methane oxidation were initiated at various moisture contents and temperatures. The results from the field and laboratory testing will be utilized in the development of a new methane oxidation model to predict seasonal variability in the oxidation capacity of soil methanotrophic bacteria. Methods of monitoring this project have included discussing project plans at conferences as well as teleconferences to reduce travel costs. In addition, a technical advisory committee and the California project team is consulted via email and conference calls. Monthly reports are distributed via email. It is planned in the next two years to hold the technical advisory committee meetings at the two field sites to further illustrate the methodology and field measurements occurring as part of this project.